Tunnel kiln



C. DRESSLER Oct. 18, 1927.

TUNNEL KILN Filed June l5, 1923 2 Shee'cs--SheetI 1 A TTORNE Y C. DRESSLER Oct 9 TUNNEL KILN Filed June 13, 1923 2 Sheets-Sheet 2 Patented @c't. 18, 1927.

OFFICE.

CONRAD LRESSLER SF CLEUEYUBLND, OHIQ, .ASSIGNOR TO AMERICAN DRESSLER TUN- NEI. KILNS NC., 0F CLEVELAND. OHIO, A. CRPORATON OF NEW YORK.

TUNNEL KlLli.

Application tiled June L,

My present invention relate: to tunnel kike and particularly to tunnel kilns oi the open tiritypc which are heated b v burningT gases and not products ot conuiustiou passinny info the kiln chamber proper troni tire boxes or combustion chan'ibers at the sides of the kiln; and the ob'iect ot my invention is to improve the tire box constructions of such kilns andl particularly to make simple and etl'ectirs` provisions for cooling the walls ot' the combustion chambers of such fire boxes and at the same time highly preheating the air applied to the combustion chambers to Isupport combustion therein and supplying it to said chamber to secure etlicient combu:-tion therein.

The various features ot" noveltyv which characterize my invention are pointed out with particularity in the claims annexed to and toi-nung a part of this specification. For a better understanding of the invention. however', itsl advantages and specilic objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated a preferred embodiment of my invention.

0f the drawings:

Fig. l is a diagrammatic plan view of a tunnel kiln; Y

Fig. 2 is a section on the line 2"2 of Fig.

7 u i l n Fig, 3 is a section on the hne 3-3 of Fig. 2;

ig` 4 is an elevation of the grate and ash removing means employed; and

Fig. 5 is a partial section on the line 5-#5 otI Fig. 3.

ln the drawings A represents a tunnel kiln comprising a preheating zone a, high temperature or firing zone b, and cooling zone c. The kiln is heated by hot products of combustion and burning gases passing into the kiln chamber proper from the tire boxes B suitably distributed along the sides of the high temperature or tiring zone b of the kiln The products of combustion are Withdrawn from the kiln chamber adjacent the entrance end of the latter by the stack C.

Each fire box B is a masonry structure comprising a combustion chamber B open at its inner end to the kiln chamber through a port B2 in which checker brick R may be stacked. Each re box is formed at its outer end with a fuel charging port B3 normally closed by a door D. The combustion 1921i. ieri-il NO, 645,21?.

chainw ll is provided with a depending portioi` adjacent its outer end, in the loue: portion ot which mounted the 4rate E :u: eifach the fuel is burned. A vantageonslj., though not necessarily, the grate is ct' the type shown and comprises a metalhc traine member E on which is secured tubular end members Eu and U shaped grate members liz" proper. which are spaced apart to provide outlets E4 for air su' plied through one thtA tubular members and the pipe l" connected to the outer end of the latter. The outer end of the other tubular member E closed, as by the cap E5. Mounted on the frame member E sprocket wheels (i over which run ash re movingr sprocket chains G.

'To cool the walls of each fire boX, and thereby prevent those walls from being injured hy overheating and at the same time to highlyv prehcat the air supportingr combustion provisions are made for passing such air through cooling channels in the ire boX 'alla These channels include a channel H formed in the wall surrounding the port or throat B2, through which the combustion chamber proper con'iniunicates With the interior of the kiln. As shown the channel H surrounds the port B2, and receives air at its underside through a port H from a subjacent tiue I running lengthwise of the kiln at the corresponding side of the latter. From the top of the channel H, the air passes throu h a pi )e J into an air chamber or channel Whic top of the combustion chamber proper, the combustion chamber being formed with double side and top Walls to provide for the chamber K. The lower ends of the chamber K, which is in the sha eof an inverted U, are divided into flues by masonry walls or ribs K2, which give mechanical stability to the inner Wall of the chamber K. The lower ends of the tlues K at each side of the combustion chamber are connected to a corresponding horizontal liue K3. The two flues KS are each connected to a channel L which passes under the charging port B3. The channel L is connected at one side ofthe tire box to the pipe F supplying air to the hollow grate, and the air thus supplied to the hollow grate forms the primary air of combustion for the fuel on the grate. The channels K also supply air to a Cross channel LA the top and side walls of which are envelops the sides and firm a bridge Wall in the combustion chami i i 'ront of the depending port B4 The secondary air for combustion supplied to the combustion chamber B from the cooling system throug'h suitable ports L5, M, and N. As shown the ports L5 are lead from the top of the channel LA, the ports M are located in the roof and side walls of the combustion chamber and receive air from the chamber K and its ex- Tensions K, and the ports N are located in the outer end wall of the combustion chamher at the sides of the charging port B8' and receive air from vertical branches L of the channel L at the sides of the charging portrBS, and each provided with a regulating damper L".

The air supplied to the fire box cooling channels through the fiues I may advantageously 'be air which has already been heated to some extent, and for this purpose preferably employ air previously heated cooling the ware in the cooling zone of t` e kiln or in cooling the tracks and under structure of the cars. In the construction illustrated, the air is furnished under suitable pressure by a fan P which draws heated air from the cooling zone section c of the kiln. The fan may draw air directl from the kiln chamber, or from cooling ues in the walls of the kiln chamber as in the kiln arrangement shown in the application of Paul A, Meehan, Serial No. 645,310, filed June 14, 1923. By the preliminary heating of the fire box cooling air, it is possible to obtain the desired cooling effect, and the desired amount of preheated air for supporting combustion without an undue cooling effect in the walls of the channel H into Contact with which the cooling air first comes.

l/Vith the described arrangement in Which-l tw, cooling air first flows through the chanipf- H along the underside of the throat or pmt B2, and thence up at the opposite sides et' that port in divided streams which meet above the port, and is then passed into the top of the chamber K and passes downward through the legsvof the latter to the channel L, a uniform and adequate cooling effect is obtained, and the air is properly preheated for use in combustion. It will be observed that the cooling air is at its lowest temperature when it enters the channel H where the most drastic cooling effect is desired.

The preheating of the air for secondary combustion and the manner in which this air is introduced into the combustion chamber increases the e ciency of combustion by effecting a proper intermingling of the combustible gases rising from the fuel bed and the prompt ignition of the mixture thereby making effective use of the whole' chamber B as a combustion chamber, and tends to the complete combustion of the fuel in the com-v bustion chamber. The prompt and thorough intermingling of the combustible gases with the air for combustion is insured b the comparatively large number of secon ary air admission ports L5, M, and N, and the Wide` distribution of these ports over the Wall 'of the combustion chamber. The jets discharged through these ports set up whirly and eddes in the gases passing through the combustion chamber which aid in the rapid and thorough admixture of the gases. This mixing effect may be enhanced to advantage in some cases by a special disposition of the ports M to increase their gas whirling effect. The complete combustion of the fuel in the combustion chamber is especially desirable as it avoids the inequalities in the heating effects produced in the kiln chamber which result from burn` ing a portion of the fuel gases therein. With the described arran ement in which practically all of the hig ly heated walis of the combustion chamber, and of the port B are directly cooled by the air passages H and J, the secondary air supply ports L5, M, and N, can be located wherever experience, or the conditions of operation for any particular kiln burning any particular kind of fuel, make it desirable to locate such ports. By means of the dampers J and F in the pipes J and F, respectively, the amounts of primary and secondary air supplied may be readily and separately controlled, thus permitting of an easy and accurate regulation of the rate of combustion and the character of combustion, since by varying the relative amounts of primary and secondary air supplied, the gases passing from the combustion chamber into the kiln chamber may be made oxidizing, neutral or reducing.

The provision of the ports N at the sides of the charging port BS is especially important in View of the manner in which the fire boxes of the kiln illustrated are ordinarily charged. In charging such fire boxes with coal, some of the fresh coal is left on the bottom wall of the port at each charging operation. vThis coal is partially distilled by the heat in the fire box before the following charging operation occurs, at which time the coke-like residue of the coal previously left on the bottom wall of the charging port is pushed on to the fuel bed and a new supply of fresh coal is left on the bottom wall of the port. With ports N arranged as shown. the gases of distillation from the coal in the port Ba are mixed with air and burned as they are generated. Advantageously the ports N at the opposite sides of the'charging port B3 converge toward one another as shown in Fig. 5. This facilitates the rapid ignition and thorough combustion of the said gases of distillation.

While the invention in the form illustrated is of especial utility in connection with fire boxes heated by the combustion olsolid fuel. the invent-ion in its broader as pects is not restricted to lire boxes burning any particular fuel but may be employed with suitable changes in t'orm with tire boxesy heated by the combustion ot' gas or oil.

W'h-ile in accordance with the prorisionsl of the statutes. l have illust-rated and dc scribed the best forms of my invention non' knovvn lo mc. it. willbe apparent to thosil skilled in the art that many changes in form may he made without departing from the spirit oi my invention. and that certain features of my invention may sometimes be employed to advantage without. a corresponding use of other features.

Having now described my iriv'entitn1-i'vliat l claim as neviv and desire tb secure by Let-I ters Patent, is:

l. ln an open tire kiln havingr a ire box at the side of the kiln chamber with a com bustion chamber therein and aport opening from said combustion chamber to the kiln chau'iber, the improvement which consists in cooling channels in the Walls` of said port.

and at the sides and top of said combustion chamber. and provisions for passing air through said channels into said combustion chamber to support combustion therein.

2. ln an open tire kiln having a lire. box at the side of the kiln chamber with a combustion chamber therein and a. port opening from said combustion chamber to the kiln chamber, the. improvement Which consists in cooling channels in the walls of said port and at the sides and top of said combustion chamber. ports opening from said channels directly to the combustion chamber to supply secondary air of combustion thereto. and means for passing a. portion the air from said channels to the combustion chamber to serve as primary air of combustion therein.

3. In an open fire kiln having a tire box at, the side of the, kiln chamber with a combustion chamber therein and a port opening from said combustion chamber to the kiln chamber and primary and secondary air inlets` the improvement which consists in cooling channels` in the walls of said port and at the sides and top of said combustion chamber and provisions for passing air through said channels into said inlets in regulated proportions, ports opening from said channels directly to the combustion chamber to supply secondary air of combustion thereto. and means for passing a por tion of the air from said channels to tlnv combustion chamber to form a primer-v ail ot combustion therein.

l. ln an open tire kiln having Y vherein and a iftion chamber J y rement lo.

a channel in the wall surrounding said port, a `second channel in the wall surrounding ie combustion chamber and means for passig air in series through said channels into .iid combustion chamber.

5, ln an open fire kiln having a. tire box ai the sidc of the kiln chamber with a combustion chamber therein. a port opening from said ombnstion chamber to the kiln chamber. and a fuel grate in said combusli 'n chamber. the innirovementwhich consis-ts in a channel in the Wall of said port, a cooling space in the Wall of the combustion chamber, ports opening to the combustion chamber above the fuel grate from said space. a damper controlled connection between the channels. means Jfor supplying air under pressure to the first mentioned channel and a damper controlled connection from the last mentioned channel to the combustion chamber at the underside of the fuel grate therein.

Y 6. The combination in an open re kiln of a. fire box at the side of the kiln chamber With a, combustion chamber therein, a port opening from said combustion chamber to the kiln chamber, a charging port at the front end of the combustion chamber and a door normally closing said charving port, a fuel grate in the lower portion o? thc combustion chamber onto which fuel may be pushed through said charging port, cooling channels for the Walls of the combustion chamber comprising portions in the front wall adjacent said charging port and outlets therefrom adapted to discharge jets in proximity to said port for burning the gasesv distilled from coal in said port, and means for su plying air under pressure to said channels.

7. The combination in an open fire kiln of a fire box at the side of the kiln chamber with a combustion chamber therein, a port opening 'from said combustion chamber to the kiln chamber, a charging port at the front end of the combustion chamber and a door normally closing said char ring port, a fuel grate in the lower portion o the combustion chamber onto which fuel may be pushed through said charging port, cooling channels for the ivalls of the combustion chamber comprising portions in the frontJ Wall adjacent said charging port and out lets therefrom adapted to discharge jets in proximity to said ports for burning the gases distilled from coal in said port7 and means for supl'ilying air under pressure to said channels .said outlets being shaped to deliver wnrerg y jets at the opposite sides of said cnarging port.

ln an open fini kiln having a tire box tl ii be s the l" i chamber with a ion iber in. a port oper ,sa f abn chamber to the i'c. 'i .l ln i fla/lit) Walid .1

tion chamber, the improvement which consists in a b`ridge Wall extending across said combustion chamber between said grate and port, a cooling space in the wall of the combustion chamber including a channel in said bridge Wall, and ports distributed along the length of said channel, opening from the latter to said combustion chamber.

9. In an open fire kiln having a fire box at the side of the kiln chamber With a combustion chamber therein, a port opening from said combustion chamber to the kiln chainber, and a fuel grate lin said combustion chamber, the improvement which consists in an air space in the highly heated walls of said chamber, and a multiplicity of small and widely distributed ports through which secondary air of combustion may pass `into said chamber from said spaces.

10. In an open ire kiln having a fire box at the side of the kiln chamber Wit-h a combustion chamber therein and comprising a thickened Wall portion between the kiln chamber and the lower portion of the combustion chamber and having a port opening from said combustion chamber to the kiln chamber above said thickened wall portion, the improvement which consists in a cooling space in the Wall of the combustion chamber including a channel in the upper portion of said thickened Wall portion and ports distributed along the length of said channel opening from the latter to said combustion chamber.

Signed at Cleveland in the county of, Cuyahoga and State of Chio this 8th day of June, A. D. 1923.

CONRAD DRESSLER. 

